The present invention relates to a method and apparatus that provides for communication between low message rate wireless devices and Users via monitoring, control and information systems.
To allow support for the growing number of mobile users and maintain consistent performance in terms of data speeds and access, all current mobile networks (FIG. 1) 100 have been designed to scale easily by adding more nodes (e.g., Node Bs, Mobile Switching Centers (MSCs), GPRS Serving Nodes (GGSN, SGSN), etc.) into the hierarchy. This network scalability comes with an associated signaling cost. To maintain control of this highly distributed and hierarchical network, and allow users virtually uninterrupted access, there needs to be a large volume of signaling messages (FIG. 2). The large signaling load is necessary to support: frequent authentication of users; changing locations of users within the network; setup of user connections, including reservation of network resources; release of user connections; maintenance of user connectivity to the network (i.e., handovers, power control). In this type of network architecture the signaling messages control every aspect of the users network access, including all the nodes associated with the user. Ideally, the signaling traffic is small in comparison to the overall user generated traffic; however for some types of network users and/or applications, the signaling traffic dominates over the payload traffic and can sometimes lead to signaling bandwidth becoming a chokepoint for the overall network operation. All cellular, paging and private mobile wireless networks use this hierarchical network design approach and can suffer from network problems related to signaling message overload.
Although it is technically possible to use the mobile wireless technology as described above to address many low user message rate machine-to-machine or machine-to-user applications, the associated costs are often prohibitive. A significant issue when using mobile networks (FIG. 1) 100 to serve these low user message rate applications is that there are many more signaling messages (FIG. 2) 200, 201-219 on the network than actual user data messages 220. In a typical mobile data network, more than 40 signaling messages are required to send a single payload message. While this signaling message overhead constitutes a small percentage of the total network traffic for applications such as streaming video (i.e., large volume of user/application generated messages) to a handset, for low message rate applications, there can be an order of magnitude more signaling traffic than actual payload message traffic. Even mobile devices that never send payload messages can result in substantial signaling message traffic by simply being connected to the network. In general, mobile wireless networks are optimized to deal with a moderate number of users or devices that each produce significant data message loads, rather than very large numbers of devices, each only occasionally sending or receiving a payload message. The invention described herein addresses the requirements for a network to efficiently support potentially billions of low user message rate devices.
A widely-deployed low user message rate application is remote utility meter reading (i.e., “Smart Meters”). It is a simple matter to design a low cost device that can capture meter usage data, however the more challenging part of the solution is the mechanism for delivering the data to a billing application located on the utility company servers. The current preferred approach often involves the installation of a private wireless network by the utility company to provide a link to the utility meter. The installation of the network itself can be very expensive and inefficient in terms of infrastructure utilization, as the wireless infrastructure is used to address only a single service application. Alternative implementations may use cellular data modems, however these can burden the solution with much higher device costs and recurring cellular service fees.
There are many applications that would benefit from the provision of a cost-effective low user message rate service. Virtually any device with a controller and/or information store may derive value from the addition of network connectivity. A sample list of applications that could benefit from low user message rate services is:
1. Utility Companies, as already mentioned                Meter reading (“Smart Meter”)        Transmission/Distribution line monitoring and control (“Smart Grid”)        
2. Asset Tracking                Vehicles        Pets        People        Property        Packages/retail goods        
3. Health Services                Patient vital signs        Emergency contact services        Validation of medicine use        
4. Personal Fitness                Exercise statistics        Weight measurement        Location and distances        
5. Security                Alarm monitoring        Fire/flood detection        
6. Home Automation                HVAC control        Energy use monitoring        Lighting control        Irrigation control        Appliance control        
7. Alarms                Lock control        Faults        Automatic accident reporting        
8. Information Display                Time        Weather station data        Public transit        Traffic conditions        Parking locations        
9. Public Safety                Traffic displays        Lighting control and monitoring        Flood monitoring        Weather/disaster alerts.        
A common theme for all the listed low user message rate applications is that the transmission of the device payload by the network is not sensitive to network delays or jitter. This is in contrast to a voice or video application where delay or jitter in the sending of the voice/video data will result in poor perceived performance by the listener or viewer. Consequently voice/video applications are more suited to a mobile wireless network where the delay and jitter are tightly controlled (e.g., Cellular network).
In addition the number of messages sent by these exemplary low user message rate applications listed above may range, at one upper end, from for example ten's of messages per day in the case of a GPS based asset tracker application to hardly any messages for an alarm monitor (e.g., a storage shed window open sensor) that is rarely activated. This is again in contrast to a web browser or email application where delay/jitter (i.e., latency) are not important, but there may well be thousands of messages per day in order to deliver the users content. Although a high-message-rate cellular network could support low user message rate devices/applications, the previously discussed signaling message load might be excessive for such devices with very low utilization of the network resources. If this is scaled to support billions of devices, then the cellular network may become overloaded with signaling traffic.
In some cases the low user message rate network may need an initial registration dialog to configure the device, which will require each device to transmit a few messages.
The ability to provide low user message rate services at very low costs makes the introduction of these services an economically viable option, based on: low cost/complexity wireless transceivers, very low power utilization, and the economic benefits of sharing a common wireless infrastructure to serve a multiplicity of applications.
It is therefore apparent that an urgent need exists for a network architecture and communications apparatus and method to support the deployment of very large numbers of low user message rate devices that can cost effectively and efficiently support multiple machine-to-machine and machine-to-user interactions.